The present invention relates to testing a data packet signal transceiver device under test (DUT), and in particular, testing transmission and/or reception performance of a DUT with minimal required signal interactions between a tester and the DUT.
Many of today's electronic devices use wireless signal technologies for both connectivity and communications purposes. Because wireless devices transmit and receive electromagnetic energy, and because two or more wireless devices have the potential of interfering with the operations of one another by virtue of their signal frequencies and power spectral densities, these devices and their wireless signal technologies must adhere to various wireless signal technology standard specifications.
When designing such wireless devices, engineers take extra care to ensure that such devices will meet or exceed each of their included wireless signal technology prescribed standard-based specifications. Furthermore, when these devices are later being manufactured in quantity, they are tested to ensure that manufacturing defects will not cause improper operation, including their adherence to the included wireless signal technology standard-based specifications.
Testing of such wireless devices typically involves testing of the receiving and transmitting subsystems of the device under test (DUT). The testing system will send a prescribed sequence of test data packet signals to a DUT, e.g., using different frequencies, power levels, and/or signal modulation techniques to determine if the DUT receiving subsystem is operating properly. Similarly, the DUT will send test data packet signals at a variety of frequencies, power levels, and/or modulation techniques for reception and processing by the testing system to determine if the DUT transmitting subsystem is operating properly.
For testing these devices following their manufacture and assembly, current wireless device test systems typically employ testing systems having various subsystems for providing test signals to each device under test (DUT) and analyzing signals received from each DUT. Some systems (often referred to as “testers”) include, at least, one or more sources of test signals (e.g., in the form of a vector signal generator, or “VSG”) for providing the source signals to be transmitted to the DUT, and one or more receivers (e.g., in the form of a vector signal analyzer, or “VSA”) for analyzing signals produced by the DUT. The production of test signals by the VSG and signal analysis performed by the VSA are generally programmable (e.g., through use of an internal programmable controller or an external programmable controller such as a personal computer) so as to allow each to be used for testing a variety of devices for adherence to a variety of wireless signal technology standards with differing frequency ranges, bandwidths and signal modulation characteristics.
A recent wireless local area network (WLAN) standard in the IEEE 802.11 set of specifications, known as IEEE 802.11ax, operates in existing 2.4 GHz and 5 GHz spectrums and will incorporate additional bands between 1 and 7 GHz as they become available. In addition to using MIMO and MU-MIMO, OFDMA has been introduced to improve overall spectral efficiency, and higher order 1024-QAM modulation support for increased throughput. Though the nominal data rate is just 37% higher than IEEE 802.11ac, it is expected to achieve a 4× increase to average user throughput due to more efficient spectrum utilization and improvements for dense deployments. However, requirements for 802.11ax power accuracies of transmit (TX) power and received signal strength indicator (RSSI) readings of a device are significantly more restrictive to ensure its compatibility with and operations within a WLAN.
Accordingly, TX power and RSSI must be calibrated and tested as part of the manufacturing process. While TX power testing may generally be simple and optimized for efficiency with technologies like MPS (multi packet testing), RSSI testing typically requires querying the DUT for its measured or reported RSSI value. However, querying the DUT is inefficient due to the additional test time needed to accommodate exchanges of query and reply packets.
Additionally, development software for manufacturing testing is significantly complicated by the fact that DUT calibration is often implemented differently among the chipset manufacturers as well as from chipset to chipset by a manufacturer. For example, as noted, calibration of receive (RX) signal operations is often particularly time consuming due to the need for querying the DUT for its receiver operation status and/or performance.